As much as 90 percent of the mountain lions in California may have been exposed to deadly anticoagulant rat poisons. The California Department of Pesticide Regulation is looking into changing regulations on the poison’s use.

An analysis of 11 wildlife studies has revealed some startling and worryisome information. More than 85 percent the mountain lions, bobcats and the protected Pacific fishers tested have been exposed to rat poisons. Other species showed evidence of the poison also.

“This alarming new evidence should spur the state to ban these dangerous poisons,” said Jonathan Evans, legal director of the Center for Biological Diversity’s environmental health program. “There are safer, cheaper alternatives that greatly reduce risks to wildlife, pets and children. Pesticide regulators have no excuse for continuing to allow California’s wildlife to die slow, excruciating deaths.”

The California Department of Pesticide Regulation conducted the analysis as it considers possible changes to regulations. The department released part of its findings last month.

In December 2017, the department received a letter, data and exhibits from an attorney representing Raptors Are the Solution and Project Coyote, and requesting the department re-evaluate seven pesticides — brodifacoum, bromadiolone, difethialone, difenacoum, diphacinone,, chlorophacinone and warfarin — now permitted. The groups allege the poisons, all used in rodenticides, represent significant impacts on wildlife health and the environment.

The department has found that first generation rat poisons, which require a rodent to eat the poisoned bait multiple times in order to kill it, does not pose a substantial risk to wildlife. However, they have found that second generation poisons, which kill with one dose, appear to cause risk and should be re-evaluated.

In 2014, the state set restrictions on second-generation anticoagulant poisons, barring their sale to residents, but allowing licensed applicators to use them. They also are permitted for agriculture and farming use to control rodents that threaten crops.

The problem with poisons is not that a mountain lion, bobcat or coyote eats it. It’s that they feed on rodents that have eaten it, becoming unintentional victims. Although eating one poisoned rat usually isn’t enough to kill a larger animal, eating several could be. There also is evidence that the cumulative effect of the poison can lead to death or serious health issues.

The Department of Pesticide Regulation had set Dec. 17 as the deadline for interested people to make comment on the use of the pesticides. However, in response to several requests, the department extended the deadline through Jan. 16.

Comments may be submitted to the Department of Pesticide Regulation, Pesticide Registration Branch, 1001 I Street, P.O. Box 4015, Sacramento 95812-4015. Comments also can be submitted by email to Rodenticide.Comments@cdpr.ca.gov.

The department’s analysis documented rat poisons in more than 90 percent of tested mountain lions, 88 percent of tested bobcats and 85 percent of tested protected Pacific fishers. It also found that seven out of 10 endangered Northern spotted owls and 40 percent of tested barred owls had been exposed to the poison.

Nationally, more than 4,400 children under age 6 were poisoned by anticoagulant rodenticides in 2016, according to the American Association of Poison Control Centers. The Environmental Protection Agency also has found that children in low-income families are disproportionately exposed to the poisons. Thousands of incidents of pets being poisoned by rodenticides have also been reported, many resulting in serious injury or death.

There are other ways to deal with rodents, including rodent-proofing homes and yards, eliminating food sources that attract rats, using traps and encouraging the natural predation of rats by installing owl boxes.

Joan Morris is the pets & wildlife columnist for the Bay Area News Group. She also writes about gardening and is the founder of Our Garden, a demonstration garden in Walnut Creek. Morris started her career in 1978 as a reporter for a small New Mexico newspaper. She has lived in the Bay Area since 1988.